After a European patent is issued, within a period of nine months, an opposition may be filed with the European Patent Office (EPO) against the patent by any third party (generally the competitors of the patent holder), in order to invalidate or limit the patent, in a centralised and retroactive manner. The opposition applies in all designated States.

It may be based on one of the following grounds:

  • the object of the patent is not patentable (e.g. lack of novelty or inventive activity)
  • the invention has not been described in a sufficiently clear and complete manner for a person skilled in the profession to execute it (insufficient description)
  • the object of the issued patent extends beyond the contents of the application, as it was filed.

After this procedure, the patent is:

  • either retained as issued, with the opposition being rejected
  • or retained in a modified form
  • or revoked.

Opposition is therefore a major challenge in the life of a European patent from a strategic point of view, for the patent holder as well as for all its competitors. It is an extremely complicated and formal procedure (the filing of an opposition must meet extremely strict conditions, and may be declared inadmissible for technicality or for missing a deadline, for instance) that requires having knowledge about the technique as well as about industrial property, which is why it is strongly recommended to rely on the expertise of authorised attorneys before the EPO.

Our patent engineers, authorized attorneys before the EPO, are qualified to assist you, advise you and represent you at every stage of this procedure, whether it is for the defense of your patent or for opposing a third-party patent.


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